Modeling and Simulation of the Impact of Temperature on Single Point Load Cell using Trnsys 16.0: Measured, Uncompensated and Error Data for Zaria Kaduna State

Abstract

A load cell is a piece of machined metal called a transducer or load sensor. As a measuring device, the entire framework is prone to the impact of environmental forces which can produce errors in the load cell output. The most significant force or input modifier is high ambient temperature. Typical meteorological year document demonstrates that in March, April, and May the temperature in Zaria can surpass 40ºC degrees on some days, including in most parts of northern Nigeria. It then implies that most weighing scales in the open environment will normally have a diminished sensitivity and along these lines yield wrong outcomes which can affect critical decisions with respect to weight control and well-being. Thus, this research aims to model and simulate the impact of high ambient temperature on a load cell using TRNSYS simulation studio. And its specific objectives are; to develop the model mathematically using the method of high gain feedback in a closed-loop to measure and compensate for errors due to ambient temperature above 40°C, to program the model using FORTRAN programming language at the back end, to simulate the model using a typical year meteorological weather data file for Zaria (11.0855°N, 7.7199°E). The procedures to model and simulate the effect of high ambient temperatures on load cell sensitivity include; the development of the model mathematically using the equation for high gain feedback in a closed-loop, programing the model using FORTRAN programming language (g 95 in Code block IDE), simulation of the model using a typical year meteorological weather data file for Zaria, (obtainable from meteorological Agencies). In the simulation, 75 kg was used as the sample weight. And the data obtained shows that in March at 1416.0 h, when no load is applied, there is a drift in the output range of the system even though the ambient temperature 20.152°C is within the scope of load cell compensation. Noticeably, the feedback system re-calibrated the scale thus eliminating the error and returning the gauge to 0.0 kg. The highest ambient temperature in March was recorded at 1981.0 h as 47.246°C with a corresponding error of 0.142. The feedback system evaluates the uncompensated value, eliminates the error and returns a correct value of 75 kg corresponding to the measured value. In April a drift in the system output range was also noticed at 2160.0 h, with a corresponding error of 0.150 before the feedback system re-calibrated the scale to 0.0 kg. The highest ambient temperature for April is 46.48°C at 2292.0 h and the corresponding error is 0.139. The feedback system again evaluates the uncompensated value, resolves the error and returns 75 kg corresponding to the measured value or known weight. While in May a drift in the system output range was also noticed at 2880.0 and the feedback system quickly returns the value to 0.0 kg. The highest ambient temperature of 46.86 is seen at 3037.0 h with a corresponding error of 0.141. The feedback system again evaluates the uncompensated value, resolves the error and returns 75 kg corresponding to the measured value.